Pool season · Montana
Missoula Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Missoula's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.
Each dot on the bar is one week of Missoula's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (May 31–June 21), solid teal is swim season, and hollow amber is the closing window ending September 18. The black marker is today — its position against the colors is the entire executive summary.
The Missoula pool calendar
Opening — target June 7
Open by June 7 — a two-week head start on the June 21 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline September 18
The window opens September 8 once water leaves the algae zone; the model deadline is September 18, a week ahead of the October 1 freeze normal.
Estimated water temperature by month
This is Missoula's typical-year water curve: the same EWMA model as the live widget, run on the 1991–2020 normals instead of this week's weather.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26° | 28° | 35° | 42° | 50° | 57° | 65° | 70° | 63° | 52° | 39° | 29° |
The curve peaks near 70°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Missoula hits the closing window
Data: NOAA 1991–2020 climate normals via Missoula 2 NE (3.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.